Simple Multifactor Authentication
Allow CAS to act as a multifactor authentication provider on its own, issuing tokens and sending them to end-users via pre-defined communication channels such as email or text messages. Tokens issued by CAS are tracked using the ticket registry and are assigned a configurable expiration policy controlled via CAS settings.
Configuration
Support is enabled by including the following module in the overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-simple-mfa</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-simple-mfa:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-simple-mfa"
}
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.bypass.groovy.location=
The location of the resource. Resources can be URLS, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256. You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.
|
cas.authn.mfa.simple.bypass.rest.url=
The endpoint URL to contact and retrieve attributes. |
cas.authn.mfa.simple.bypass.authentication-attribute-name=
Skip multifactor authentication based on designated authentication attribute names. |
cas.authn.mfa.simple.bypass.authentication-attribute-value=
Optionally, skip multifactor authentication based on designated authentication attribute values. |
cas.authn.mfa.simple.bypass.authentication-handler-name=
Skip multifactor authentication depending on form of primary authentication execution. Specifically, skip multifactor if the a particular authentication handler noted by its name successfully is able to authenticate credentials in the primary factor. |
cas.authn.mfa.simple.bypass.authentication-method-name=
Skip multifactor authentication depending on method/form of primary authentication execution. Specifically, skip multifactor if the authentication method attribute collected as part of authentication metadata matches a certain value. |
cas.authn.mfa.simple.bypass.credential-class-type=
Skip multifactor authentication depending on form of primary credentials. Value must equal the fully qualified class name of the credential type. |
cas.authn.mfa.simple.bypass.http-request-headers=
Skip multifactor authentication if the http request contains the defined header names. Header names may be comma-separated and can be regular expressions; values are ignored. |
cas.authn.mfa.simple.bypass.http-request-remote-address=
Skip multifactor authentication if the http request's remote address or host matches the value defined here. The value may be specified as a regular expression. |
cas.authn.mfa.simple.bypass.principal-attribute-name=
Skip multifactor authentication based on designated principal attribute names. |
cas.authn.mfa.simple.bypass.principal-attribute-value=
Optionally, skip multifactor authentication based on designated principal attribute values. |
cas.authn.mfa.simple.bypass.rest.basic-auth-password=
If REST endpoint is protected via basic authentication, specify the password for authentication. |
cas.authn.mfa.simple.bypass.rest.basic-auth-username=
If REST endpoint is protected via basic authentication, specify the username for authentication. |
cas.authn.mfa.simple.bypass.rest.headers=
Headers, defined as a Map, to include in the request when making the REST call. Will overwrite any header that CAS is pre-defined to send and include in the request. Key in the map should be the header name and the value in the map should be the header value. |
cas.authn.mfa.simple.bypass.rest.method=GET
HTTP method to use when contacting the rest endpoint. Examples include |
cas.authn.mfa.simple.failure-mode=CLOSED
The failure mode policy for this MFA provider. The authentication policy by default supports fail-closed mode, which means that if you attempt to exercise a particular provider available to CAS and the provider cannot be reached, authentication will be stopped and an error will be displayed. You can of course change this behavior so that authentication proceeds without exercising the provider functionality, if that provider cannot respond. Each defined multifactor authentication provider can set its own failure mode policy. Failure modes set at this location will override the global failure mode, but defer to any failure mode set by the registered service. Available values are as follows:
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cas.authn.mfa.simple.id=
The identifier for the multifactor provider. In most cases, this need not be configured explicitly, unless multiple instances of the same provider type are configured in CAS. |
cas.authn.mfa.simple.name=
The name of the authentication handler used to verify credentials in MFA. |
cas.authn.mfa.simple.order=
The order of the authentication handler in the chain. |
cas.authn.mfa.simple.rank=0
At times, CAS needs to determine the correct provider when step-up authentication is required. Consider for a moment that CAS already has established an SSO session with/without a provider and has reached a level of authentication. Another incoming request attempts to exercise that SSO session with a different and often competing authentication requirement that may differ from the authentication level CAS has already established. Concretely, examples may be:
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cas.authn.mfa.simple.time-to-kill-in-seconds=30
Time in seconds that CAS tokens should be considered live in CAS server. |
cas.authn.mfa.simple.token-length=6
The length of the generated token. |
cas.authn.mfa.simple.trusted-device-enabled=false
Indicates whether this provider should support trusted devices. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
Registration
Registration is expected to have occurred as an out-of-band process. Ultimately, CAS expects to fetch the necessary attributes from configured attribute sources to determine communications channels for email and/or sms. The adopter is expected to have populated user records with enough information to indicate a phone number and/or email address where CAS could then be configured to fetch and examine those attributes to share generated tokens.
Communication Strategy
Users may be notified of CAS-issued tokens via text messages and/or email. The authenticated CAS principal is expected to carry enough attributes, configurable via CAS settings, in order for CAS to properly send text messages and/or email to the end-user. Tokens may also be shared via notification strategies back by platforms such as Google Firebase, etc.
To learn more about available options, please see this guide or this guide, or this guide.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.mail.attribute-name=mail
Principal attribute name that indicates the destination email address for this message. The attribute must already be resolved and available to the CAS principal. |
cas.authn.mfa.simple.mail.from=
Email from address. |
cas.authn.mfa.simple.mail.subject=
Email subject line. This setting supports the Spring Expression Language. |
cas.authn.mfa.simple.sms.attribute-name=phone
Principal attribute name that indicates the destination phone number for this SMS message. The attribute must already be resolved and available to the CAS principal. |
cas.authn.mfa.simple.sms.from=
The from address for the message. |
cas.authn.mfa.simple.sms.text=
The body of the SMS message. |
cas.authn.mfa.simple.mail.bcc=
Email BCC address, if any. |
cas.authn.mfa.simple.mail.cc=
Email CC address, if any. |
cas.authn.mfa.simple.mail.html=false
Indicate whether the message body should be evaluated as HTML text. |
cas.authn.mfa.simple.mail.reply-to=
Email Reply-To address, if any. |
cas.authn.mfa.simple.mail.text=
Email message body. Could be plain text or a reference to an external file that would serve as a template. If specified as a path to an external file with an extension |
cas.authn.mfa.simple.mail.validate-addresses=false
Set whether to validate all addresses which get passed to this helper. |
The following settings may also need to be defined to describe the mail server settings:
spring.mail.default-encoding=UTF-8
Default MimeMessage encoding. |
spring.mail.host=
SMTP server host. For instance, 'smtp.example.com'. |
spring.mail.jndi-name=
Session JNDI name. When set, takes precedence over other Session settings. |
spring.mail.password=
Login password of the SMTP server. |
spring.mail.port=
SMTP server port. |
spring.mail.properties=
Additional JavaMail Session properties. |
spring.mail.protocol=smtp
Protocol used by the SMTP server. |
spring.mail.test-connection=false
Whether to test that the mail server is available on startup. |
spring.mail.username=
Login user of the SMTP server. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.
Rate Limiting
CAS is able to support rate-limiting for token requests based on the token-bucket
algorithm, via the Bucket4j project. This
means that token requests that reach a certain configurable capacity within
a time window may either be blocked or throttled to slow down. This is done to
protect the system from overloading, allowing you to introduce a scenario to allow
CAS 120 token requests per minute with a refill rate of 10 requests per
second that would continually increase in the capacity bucket.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.mfa.simple.bucket4j.bandwidth[0].capacity=120
Number of tokens/requests that can be used within the time window. |
cas.authn.mfa.simple.bucket4j.bandwidth[0].duration=PT60S
Time window in which capacity can be allowed. This settings supports the
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cas.authn.mfa.simple.bucket4j.bandwidth[0].initial-tokens=
By default initial size of bucket equals to capacity. But sometimes, you may want to have lesser initial size, for example for case of cold start in order to prevent denial of service. |
cas.authn.mfa.simple.bucket4j.bandwidth[0].refill-count=10
The number of tokens that should be used to refill the bucket given the specified refill duration. |
cas.authn.mfa.simple.bucket4j.bandwidth[0].refill-duration=PT30S
Duration to use to refill the bucket. This settings supports the
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cas.authn.mfa.simple.bucket4j.bandwidth[0].refill-strategy=GREEDY
Describes how the bucket should be refilled. Specifies the speed of tokens regeneration. Available values are as follows:
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cas.authn.mfa.simple.bucket4j.bandwidth=
Describe the available bandwidth and the overall limitations. Multiple bandwidths allow for different policies per unit of measure. (i.e. allows 1000 tokens per 1 minute, but not often then 50 tokens per 1 second). |
cas.authn.mfa.simple.bucket4j.blocking=true
Whether the request should block until capacity becomes available. Consume a token from the token bucket. If a token is not available this will block until the refill adds one to the bucket. |
cas.authn.mfa.simple.bucket4j.enabled=true
Decide whether bucket4j functionality should be enabled. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc. When possible, properties should be stored in
lower-case kebab format, such as cas.property-name=value.S ettings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.